3,000 research outputs found

    Proceedings of the 1st Space Plasma Computer Analysis Network (SCAN) Workshop

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    The purpose of the workshop was to identify specific cooperative scientific study topics within the discipline of Ionosphere Magnetosphere Coupling processes and to develop methods and procedures to accomplish this cooperative research using SCAN facilities. Cooperative scientific research was initiated in the areas of polar cusp composition, O+ polar outflow, and magnetospheric boundary morphology studies and an approach using a common metafile structure was adopted to facilitate the exchange of data and plots between the various workshop participants. The advantages of in person versus remote workshops were discussed also

    Use of Orbital Radars for Geoscience Investigations

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    Studies sponsored by NASA at the University of Kansas in cooperation with several other universities and government research agencies are substantiating the applicability of remote sensing by radar to many fields within the earth sciences, agriculture, and oceanography. 1 The purpose of this paper is to show how the properties of the radar return are used to provide geoscience information

    DE 1 RIMS operational characteristics

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    The Retarding Ion Mass Spectrometer (RIMS) on the Dynamics Explorer 1 spacecraft observes both the thermal and superthermal (50 eV) ions of the ionosphere and inner magnetosphere. It is capable of measuring the detailed species distribution function of these ions in many cases. It was equipped with an integral electrometer to permit in-flight calibration of the detector sensitivities and variations thereof. A guide to understanding the RIMS data set is given. The reduction process from count rates to physical quantities is discussed in some detail. The procedure used to establish in-flight calibration is described, and results of a comparison with densities from plasma wave measurements are provided. Finally, a discussion is provided of various anomalies in the data set, including changes of channeltron efficiency with time, spin modulation of the axial sensor heads, apparent potential differences between the sensor heads, and failures of the radial head retarding potential sweep and of the -Z axial head aperture plane bias. Studies of the RIMS data set should be conducted only with a thorough awareness of the material presented here, or in collaboration with one of the scientists actively involved with RIMS data analysis

    Chemical dynamics of triacetylene formation and implications to the synthesis of polyynes in Titan's atmosphere

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    For the last four decades, the role of polyynes such as diacetylene (HCCCCH) and triacetylene (HCCCCCCH) in the chemical evolution of the atmosphere of Saturn's moon Titan has been a subject of vigorous research. These polyacetylenes are thought to serve as an UV radiation shield in planetary environments; thus, acting as prebiotic ozone, and are considered as important constituents of the visible haze layers on Titan. However, the underlying chemical processes that initiate the formation and control the growth of polyynes have been the least understood to date. Here, we present a combined experimental, theoretical, and modeling study on the synthesis of the polyyne triacetylene (HCCCCCCH) via the bimolecular gas phase reaction of the ethynyl radical (CCH) with diacetylene (HCCCCH). This elementary reaction is rapid, has no entrance barrier, and yields the triacetylene molecule via indirect scattering dynamics through complex formation in a single collision event. Photochemical models of Titan's atmosphere imply that triacetylene may serve as a building block to synthesize even more complex polyynes such as tetraacetylene (HCCCCCCCCH)

    Normal Mode Spectra of Idealized Baroclinic Waves

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    © Copyright 2020 American Meteorological Society (AMS). For permission to reuse any portion of this work, please contact [email protected]. Any use of material in this work that is determined to be “fair use” under Section 107 of the U.S. Copyright Act (17 U.S. Code §?107) or that satisfies the conditions specified in Section 108 of the U.S. Copyright Act (17 USC § 108) does not require the AMS’s permission. Republication, systematic reproduction, posting in electronic form, such as on a website or in a searchable database, or other uses of this material, except as exempted by the above statement, requires written permission or a license from the AMS. All AMS journals and monograph publications are registered with the Copyright Clearance Center (https://www.copyright.com). Additional details are provided in the AMS Copyright Policy statement, available on the AMS website (https://www.ametsoc.org/PUBSCopyrightPolicy).Normal modes are used to investigate the contributions of geostrophic vortices and inertia–gravity waves to the energy spectrum of an idealized baroclinic wave simulation. The geostrophic and ageostrophic modal spectra (GE and AE, respectively) are compared to the rotational and divergent kinetic energy (RKE and DKE, respectively), which are often employed as proxies for vortex and wave energy. In our idealized f-plane framework, the horizontal modes are Fourier, and the vertical modes are found by solving an appropriate eigenvalue problem. For low vertical mode number n, both the GE and AE spectra are steep; however, for higher n, while both spectra are shallow, the AE is shallower than the GE and the spectra cross. The AE spectra are peaked at the Rossby deformation wavenumber kR n , which increases with n. Analysis of the horizontal mode equations suggests that, for large wavenumbers k kR n , the GE is approximated by the RKE, while the AE is approximated by the sum of the DKE and potential energy. These approximations are supported by the simulations. The vertically averaged RKE and DKE spectra are compared to the sum of the GE and AE spectra over all vertical modes; the spectral slopes of the GE and AE are close to those of the RKE and DKE, supporting the use of the Helmholtz decomposition to estimate vortices and waves in the midlatitudes. However, the AE is consistently larger than the DKE because of the contribution from the potential energy. Care must be taken when diagnosing the mesoscale transition from the intersection of the vortex and wave spectra; GE and AE will intersect at a different scale than RKE and DKE, despite their similar slopes.Funding from the Natural Sciences and Engineering Research Council of Canada (Grant RGPIN-386456-2015

    Particle tracking in a salinity gradient: A method for measuring sinking rate of individual phytoplankton in the laboratory

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    This paper presents a new method to measure the sinking rates of individual phytoplankton “particles” (cells, chains, colonies, and aggregates) in the laboratory. Conventional particle tracking and high resolution video imaging were used to measure particle sinking rates and particle size. The stabilizing force of a very mild linear salinity gradient (1 ppt over 15 cm) prevented the formation of convection currents in the laboratory settling chamber. Whereas bulk settling methods such as SETCOL provide a single value of sinking rate for a population, this method allows the measurement of sinking rate and particle size for a large number of individual particles or phytoplankton within a population. The method has applications where sinking rates vary within a population, or where sinking rate-size relationships are important. Preliminary data from experiments with both laboratory and field samples of marine phytoplankton are presented here to illustrate the use of the technique, its applications, and limitations. Whereas this paper deals only with sinking phytoplankton, the method is equally valid for positively buoyant species, as well as nonbiological particles

    Binding loci of RelA-containing nuclear factor-kappaB dimers in promoter regions of PHM1-31 myometrial smooth muscle cells.

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    Human parturition is associated with many pro-inflammatory mediators which are regulated by the nuclear factor-kappaB (NF-κB) family of transcription factors. In the present study, we employed a ChIP-on-chip approach to define genomic loci within chromatin of PHM1-31 myometrial cells that were occupied by RelA-containing NF-κB dimers in response to a TNF stimulation of 1 h. In TNF-stimulated PHM1-31 cells, anti-RelA serum enriched 13 300 chromatin regions; importantly, 11 110 regions were also enriched by anti-RelA antibodies in the absence of TNF. DNA sequences in these regions, from both unstimulated or TNF-stimulated PHM1-31 cultures, were associated with genic regions including IκBα, COX-2, IL6RN, Jun and KCNMB3. TNF-induced binding events at a consensus κB site numbered 1667; these were represented by 112 different instances of the consensus κB motif. Of the 1667 consensus κB motif occurrences, 770 (46.2%) were identified within intronic regions. In unstimulated PHM1-31 cells, anti-RelA-serum-enriched regions were associated with sequences corresponding to open reading frames of ion channel subunit genes including CACNB3 and KCNB1. Moreover, in unstimulated cells, the consensus κB site was identified 2116 times, being defined by 103 different sequence instances of this motif. Of these 2116 consensus κB motifs, 1089 (51.5%) were identified within intronic regions. Parallel expression array analyses in PHM1-31 cultures demonstrated that TNF stimulated a >2-fold induction in 51 genes and a fold repression of >1.5 in 18 others. We identified 14 anti-RelA-serum-enriched genomic regions that correlated with 17 TNF-inducible genes, such as COX2, Egr-1, Jun, IκBα and IL6, as well as five regions associated with TNF-mediated gene repression, including Col1A2

    How Can eHealth Meet the Hearing and Communication Needs of Adults With Hearing Impairment and their Significant Others? A Group Concept Mapping Study

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    Objectives: To seek the perspectives of key stakeholders regarding: (1) how eHealth could help meet the hearing and communication needs of adults with hearing impairment and their significant others; and (2) how helpful each aspect of eHealth would be to key stakeholders personally. / Design: Group concept mapping, a mixed-methods participatory research method, was used to seek the perspectives of key stakeholders: adults with hearing impairment (n = 39), significant others (n = 28), and hearing care professionals (n = 56). All participants completed a short online survey before completing one or more of the following activities: brainstorming, sorting, and rating. Brainstorming required participants to generate ideas in response to the focus prompt, “One way I would like to use information and communication technologies to address the hearing and communication needs of adults with hearing loss and their family and friends is to….” The sorting task required participants to sort all statements into groups that made sense to them. Finally, the rating task required participants to rate each of the statements according to “How helpful would this idea be to you?” using a 5-point Likert scale. Hierarchical cluster analysis was applied to the “sorting” data to develop a cluster map using the Concept Systems software. The “rating” data were subsequently analyzed at a cluster level and an individual-item level using descriptive statistics. Differences in cluster ratings between stakeholder groups were examined using Kruskal-Wallis tests. / Results: Overall, 123 statements were generated by participants in response to the focus prompt and were included in subsequent analyses. Based on the “sorting” data and hierarchical cluster analysis, a seven-cluster map was deemed to be the best representation of the data. Three key themes emerged from the data, including using eHealth to (1) Educate and Involve Others; (2) Support Aural Rehabilitation; and (3) Educate About and Demonstrate the Impacts of Hearing Impairment and Benefits of Hearing Rehabilitation. Overall median rating scores for each cluster ranged from 3.97 (educate and involve significant others) to 3.44 (empower adults with hearing impairment to manage their hearing impairment from home). / Conclusions: These research findings demonstrate the broad range of clinical applications of eHealth that have the capacity to support the implementation of patient- and family-centered hearing care, with self-directed educational tools and resources typically being rated as most helpful. Therefore, eHealth appears to be a viable option for enabling a more biopsychosocial approach to hearing healthcare and educating and involving significant others in the hearing rehabilitation process without adding more pressure on clinical time. More research is needed to inform the subsequent development of eHealth interventions, and it is recommended that health behavior change theory be adhered to for such interventions
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